An automatic faucet device has been known which is structured such that, when hands are extended under a faucet, a sensor senses them and water is made to flow from a faucet automatically. Further, in recent years, an automatic faucet device has been known in which a small hydraulic power generating device is arranged at a middle position of a flow path of tap water and electric power obtained by the hydraulic power generating device is stored to supply the electric power to a sensor circuit or the like of the automatic faucet device.
The hydraulic power generating device includes a case which structures a flow path from a fluid inlet to a fluid outlet, a support shaft which is disposed at a middle position of the flow path, and a cylindrical power generating hydraulic turbine which is rotatably supported by the support shaft. A conventional power generating hydraulic turbine is provided with a cylindrical part, blades which are projected from an outer peripheral face of the cylindrical part, and radial bearings having a shaft hole through which a support shaft is penetrated, and the radial bearings are integrally formed with the cylindrical part by resin molding (see, for example, Japanese Patent Laid-Open No. 2004-340111).
In the hydraulic power generating device as described above, there is commonly a clearance between the shaft hole of the power generating hydraulic turbine and the support shaft. Further, since the power generating hydraulic turbine is rotated by water which is ejected from an ejection port to be hit to the blade of the power generating hydraulic turbine, a positional relationship between the blade and the ejection port varies with rotation of the power generating hydraulic turbine and thus a direction of a force that is applied to the power generating hydraulic turbine varies. As a result, when the power generating hydraulic turbine is rotated, rotational vibration or rotation noise may occur.
When the power generating hydraulic turbine is integrally resin-molded with radial bearings, a high degree of accuracy is not attained in a dimension of an inner diameter of the shaft hole of the radial bearing due to influences of shrinkage or the like, and thus rotation noise may occur when the power generating hydraulic turbine is rotated. Further, when the radial bearings are integrally resin-molded at both ends of the cylindrical part on which the blades are projected from its outer peripheral face, dispersion may occur in size of the shaft holes of respective radial bearings due to influence of shrinkage or the like. In this state, concentric positions of the shaft holes of the respective radial bearings cannot be obtained. Therefore, a large clearance is required to be provided between the shaft hole of the radial bearing and the support shaft. However, when such a large clearance is provided, rotation noise may occur when the power generating hydraulic turbine is rotated.